Application is being made for the purchase of an Electron Paramagnetic Resonance Spectrometer which will provide for enhanced capability of the Kent State users' group in its investigations of changes in plasma membranes during cell maturation and transformation and in response to substances which act by alteration of membrane structure and function. Biochemical and biophysical modifications of the plasma membrane of spermatozoa which occur during maturation will be examined using electron spin resonance (ESR) techniques and compared with alterations of cell metabolism at various stages of development. Study of live spermatozoa by this means will enable the acquisition of much improved data on the process of capacitation, how the tubal environment in which spermatozoa develop may affect this process, and may lead to new procedures for regulating male fertility. Changes in plasma membranes which occur during cellular transformation leading to neoplastic states will also be studied with these techniques, particularly with respect to the interaction of clinically effective drugs and the effects of free radical formation on membrane properties. Structural elements and the interaction of protein and lipid components of membranes will also be examined as an extension of current NMR studies: the effects of anesthetics, fatty acids, cholesterol, and inorganic ions on protein-lipid interactions in the bilayer will be analyzed. As a result of these studies, it is anticipated that a more complete understanding of cell membranes and their alterations during normal and pathological cell changes as well as the interaction of drugs and other substances will be obtained and should contribute to the design of improved methods of intervention.